CD V-700 Geiger Counter Civil Defense Radiation Detector The detector on the CD V-700 is a Geiger-Mueller (GM) tube. It measures gamma and also beta radiation. The range selector switch allows you to measure up to 50 mR/hr. A milliroentgen (mR) is one thousandth of a Roentgen (R). The probe on the CD V-700 has a section in the center which rotates to expose a window for also detecting beta. When the window is open it detects both beta and gamma. The CD V-700 is very well suited for verifying successful decontamination and/or checking for low-level contamination in food or water. Developed to check food and shelter entrances for fallout contamination Still is use by first responders survival equipment The ruggedized lens provided more EMP protection than the original meter face Sold As Is No Warranty No radiation source iincluded